(a) Field of the Invention
The present invention relates to an automotive headlamp unit with an aiming device, and more particularly to an automotive headlamp unit provided with a simple device for providing an easy and accurate aiming adjustment of the optical axis with respect to the plane of the ground without the necessity of using any special device such as an aimer, aiming screen or the like at a car repair/maintenance shop as well as at the automobile production line.
(b) Description of the Prior Art
It is important with automotive headlamp units to properly adjust the orientation of the optical axis. If the optical axis is directed excessively upward, the light from the headlamp will dazzle the driver of a car running in the opposite lane. On the contrary, if the optical axis is orientated excessively downward, the relatively far area in front of the car cannot be sufficiently illuminated. So, various rules and regulations are imposed upon the headlamp units for optimum alignment of the optical axis from the standpoint of safe driving.
The optical axis is usually aligned after the headlamp units are installed on the body of a car. The optical-axis orientating device provided in an automotive headlamp unit of such a type as has a lamp housing receiving a reflector and a front lens, the lamp housing and front lens being formed integrally with each other, and which is intended to align the optical axis or adjust the luminous intensity distribution pattern consisting of pivot mechanisms which support, for example, the lamp housing pivotably in relation to the car body and two adjusting screws which turn the lamp housing vertically (about the horizontal axis) and horizontally (about the vertical axis), respectively. For inspecting, if the optical axis is properly orientated so that the rays of light emitted frontwardly from the headlamp units form an optimum luminous intensity distribution pattern, an aimer is used. The inspection of the optical axis alignment using such aimer needs three index protrusions, that is, aiming bosses, provided on the outer surface of the front lens and which aid to mount the aimer in a correct position. Such aiming bosses esthetically spoil the appearance of the front lens, and it is difficult with such inspection using the aimer to accurately check if the optical axis of a headlamp unit of which the front lens is disposed as slanted with an angle of less than 90 degrees with respect to the optical axis, so-called a slant-type headlamp, is properly orientated.
Furthermore, the car service centers and car repair/ maintenance shops of middle or small scale must bear expenses for new equipment since an inspection device such as an aimer is necessary when they are requested by a client to replace a damaged headlamp with a new one.